Reaction brush holder with radial adjustment



Oct. 8, 1929. J. L. BROWN REACTION BRUSH HOLDER WITH RADI AL ADJUSTIENT Filed March 27, 1928 2 ShetS-Sheet l R O T N E V N John L, Brown ATT oRNEY Oct. 8, 1929. J. L. BROWN 1,730,913

REACTION BRUSH HOLDER WITH RADIAL ADJUSTIENT Filed March 27, 1928 2 Sheets-Sheet 2 v 'I Z x 52 53 43 43 4 47 INVENEI'OR John L. Brown ATTbRNEY Patented Oct. 8, 1929 JOHN L. BROWN, OF VERONA, PENNSYLVA NIA, ASSIGNOR TO WESTINGHOUSE ELEC- TRIO & MANUFACTURING COMPANY, A. CORPORATION OF PENNEEYLVANEA REACTION BRUSH HOLDER WITH RADIAL ADJUSTMENT Application filed March Q7, 1928. Serial No. 264,988.

My invention relates to brushholders for 5 and 5 dynamo-electric machines and has particular relation to holders of the reaction type adaptable to be supported by rods.

The object of my invention is to provide a brush-holding structure that is pivotally mounted on a clamped supporting member which is rigidly carried by the brush rod of a dynamo-electrie machine, whereby the structure may be rotated on the clamped member to provide adjustment of the brush in a direction normal to the axis of the machine, without loosening the clamp or supporting member from the rod.

My invention resides in a brushholder of the character hereinafter described and shown in the accompanying drawings, wherein:

Figure 1 is a plan view taken at a right angle to the plane A-B of Fig. 2,

Fig. 2 is an elevational view, partly in section, showing my preferred form of brushholder in position before the commutator cylinder has undergone any wear,

Fig. 3 is a development of a U-shape member which is shown in Fig. 2,

Fig. 4 is a perspective view of the U-shape member having a cross-piece adjustment member disposed thereon,

Fig. 5 is a plan view of the clamped supporting member shown in Fig. 2,

Fig. 6 is an elevationad view showing a modified form of my invention having the brushholder structure disposed in a position after the commutator has undergone considerable wear, the worn portion of the commutator being shown in dotted lines,

Fig. 7 is a plan view of a frame member embodied in the structure shown in Fig. 6, and

Fig. 8 is a perspective view of a U-shape member utilized for securing adjustment in the brushholder shown in Fig. 6.

In Figs. 1 and 2 is illustrated a preferred form of my invention wherein a cast-metal supporting member 1 is clamped to a brush rod 2 of a dynamo-electric machine and carries a pivotal support 3 for a brushholding member 4 comprising two side plates 5 and 5". The bottom edges of the two side plates have slots or recesses 6 cut therein to fit over the brush rod 2 as the brushholder is pivotally adjusted on its pivot 3. The brushholder 4 is held in its adjusted position by means of a bolt 7 screy ing into the stationary clamp member 1 and having a head 8 that pulls down on a cross-piece 9 of the brushholder, the bolt being surrounded by a spring 10 that pushes up on the brushholder. T he cross-piece 9 is preferably carried by a separate U-shape member 11, of bent or stamped sheet metal, which is disposed between the two side plates 5 and 5 of the briilshholder.

The cross-piece member 9 of the brushholder has rectangular tabs or projections 12 which are supported in similarly shaped slots 12 in the sides of the U-shape member 11. The cross-piece 9 also has a slightly elongated hole 12 for receiving the adjusting bolt 7, the elongation being for the purpose of allowing the necessary slight rocking of the bolt in the hole when the brushholder is adjusted on its pivot 3.

The clamp or supporting member 1, in the form of my invention shown in Figs. 1 and 2, is made of cast material having good electrical conductivity and is clamped firmly to the rod 2, by means of a screw 13 and loelcwasher 13 when the brushholder is first installed. By reason of the separate pivotal mounting 3 of the brushholder it is not necessary to unclamp the supporting member 1 in order to adjust the brushholder 4:. By reason of the permanent clamping connection between the support 1 and the rod 2, a good electrical contact is maintained with the rod 2, and I also avoid the dii'liculty which has heretofore come from grooving the rod by contact with the clamping screw, which would re sult in the loosening of the brushholder.

My brushholder 4 is of the kind commonly known as the reaction type, wherein the carbon brush 16 has its top 17 beveled, or cut at an angle. so that the brush is held against the guiding surface of an open brush box, in this case, the back 18 of the sheetmetal V shape member 11, by a component of the reaction of the pressure finger 19 which presses against the top of the brush, the

brush being held agains lateral displace ment by the projecting ends 19 of the side plates 5 and 5 If the angle of the top surface of the brush is proper, the commutator cylinder may be rotated in either direction and the brush will still be maintained and guided by the brush box 18, 19 of the brushholder. 7 i

In the particular embodiment of my invention shown in Figs. 1 and 2, the pressure finger 19 is pivoted to the side plates 5 and 5 of the brushholder, as indicated at 20 in Fig. 2, and is biased by means of a coil spring 21 which is disposed on a sleeve 22 surrounding the pivot pin 20. One end of the coil spring bears against the brushholder, or the supporting member therefor, as indicated at 23, and the other end is adjustably engaged in teeth 24' provided in the side of the pressure finger.

In order to save space, the back plate 18 of the sheet-metal U-shape member 11 may have a window 25 wherein a corner portion of the clamp member 1 may be nested when the brushholder is adjusted, on its pivot 3, to the extreme upper limit of its adjustment.

The brush 16 is preferably grounded to the brushholder 4, and hence to the supporting pin or rod 2, by means of a flexible conductor or shunt 26, which may be of ordinary construction. V

In brushholders of the reaction type, to which my invention is particularly directed, it is particularly important to have the reaction surface, as 18, of the brushbox inclined at justthe proper angle with respect to the commutator, and spaced at just the properdistance from the commutator. As the commutator wears, therefore, it is necessary to adjust the entire brushholder, including the brushbox and pressure finger, bodily toward the commutator, in order to preserve the proper spacings and angles.

7 An important feature of my invention resides in the proper positioning of the clamped supporting member 1 with respect to the commutator. The object is to cause the'brush box part 18, 19 of the brushholder 4, to move as nearly radially as possible, when-the boltis adjusted in order to rotate the brushholder through a small arc about its pivot 3. Thebottom of the brush 16 thus describes arc, 2'-. -28 with thepivotB as center, when the brushholder is adjusted to compensate for commutator wear. This arc, being very small with respect to the radius of curvature,

is substantially. a: straight line; The center 3 lies in a perpendicular bisecting the chord 2728, and'ifthe chord is disposed in a radial direction, the center 3imust'therefore lie in aline29-30 which is tangent to the surface of the commutator cylinder 31 at the center of the brush-contact when the commutator has worn toapproximately onerhalf of the depth to which it may wear and still be operative.

The brushholder shown in Figs. 1 and 2 is made of parts which are readily detached and replaced when the entire structure is removed from the pin 2. It thus has advantages of economy and small space requirements which are particularly desirable in brushholders for small machines, and it embodies the most important feature of my invention, which is the pivotal mounting 3 whereby the brushboX 18, 19 is substantially radially adjustable, to compensate for commutator-cylinder wear, without disturbing the clamp connection with the brush rod or pin 2. It is necessary, however, in order to remove the brushholder from the machine, to slide it from the end of the pin, which is a disadvantage in certain machines where there is not sufiicient room for this purpose, and in large machines where there are many brushholders on each rod.

In Fig. 6, therefore, I have shown another embodiment of. my invention, wherein the same permanently clamped mounting on the pin is retained, and the same pivotal adjust ment to the brushholder to compensate for armature-cylinder wear, but wherein the brushholder, and all parts except theclamp which engages the brush-supporting rod, are removable without sliding the brushholder from the end of the rod. I

The brushholder shown in Fig. 6 comprises a sheet-metal support or clamp 41, which engages the brush-supporting pin or rod 2; a so-called adjustment-arm 43, of cast metal, which lies over the clamp 41 and extends beyond the pin 2, being secured to the clamp by bolts 44, 45; a cast-metal brushholder 46, (shown detached in Fig. 7), which is mounted on a pivot-pin 47 carried between the clamp 41 and the adjustment-arm 43; and a pressure finger 48 which is mounted on the brushholder ina manner similar to that already described for the finger 19 in'Fig. 1.

The brushholder 46, as shown in Figs. 6 and 7, is an integral lJ-shape frame comprising' two side walls 50 and51 connected, at one end, by an integral cross-plate 52 which constitutes the reaction surface of an open brushbox against which a brush 53 of the reaction type is pressed, as in the embodiment shown in Fig; 1. Instead of having the side plates of the brushholder extend beyond the reac ion surface, as in Fig. 1, to prevent lateral displacement of the brush, 1 may provide a separate strap or retainer 54, of sheet metal, which is suitably secured to the sides of the brushholder, and which not only prevents the lateral displacement of thebrush during actual use, but also prevents the falling out of the brush when the pressure finger 48 is momentarily lifted for inspection or test.

The brushholder-46 is held in its adjusted position by means ofa sheet metal clip 55,

which is secured to the inner face of the cross plate 52, and which carries a bolt 56 adapted to tighten up on an arcuate slot 57 in the adjustment arm 4-3, the center of curvature of the slot 57 being the pivot-pin 47.

In Fig. (3, the brushholder is shown in a rotated position after a certain portion of the commutator cylinder has been worn away, as indicated by dotted lines 58, to show that the relative positions of the clamp 41 and the ad justment arm 43 are the same as before the wearing took place, thereby illustrating the fact that the clamped support 41 need not be loosened on the brush rod 2 for rotation or adjustment of the supporting member as a whole.

'lhroughout the description of my invention, various featur s have been pointed out and it is quite possi do to utilize a feature of one form in the other form, depending upon the type of machine on which brushholders are to be installed. I *ish to have it understood, therefore, that the il ustrated arrangements have been made only with the object of illustrating my invention in brushholder which will give a substantially straight-line movement of the brush, and which may be adjusted without loosening its support.

I claim as my invention:

1. A brushholc er aggregate of the type adapted to be mounted on a single brush rod, comprising a clan'ip for engaging said rod, said clamp carrying a pivot-pin spaced from the rod at one side thereof, and parallel thereto, a brushholder pivotally mounted on said pin and terminating in a brush box disposed on the other side ofsaid rod, a brush slidably disposed in said brush box, means for pivotally adjusting said brushholder with respect to said clamp, and means adapted to yieldably press down against said brush disposed in said brush box.

2. A brushholder aggregate of the type adapted to be mounted on a single brush rod, comprising a clamp for engaging said rod, s r clamp carrying a pivot-pin spaced from the rod at one side thereof and parallel th; to. a brushholder pivot-ally mounted on said pin and terminating in an inclined brush box disposed on the other sid of said rod, a brush in said brush-box, said brush having an inclined upper surface wherel'iy said brush may be held against the back surface of said brushbox, a pressure finger carried by said brushholder and yicldably prc ing on the inclined upper surface said brush, and means for securing said brushholder in pivotally adjustable position with respect to said clamp.

3. A brushholder aggregate of the type adapted to be mounted on a single brush rod, comprising a clamp for engaging said rod, an adjustment-arm detachably secured to st id clamp, a pivot pin mounted between said adjustmentnrm and said clamp and disposed in spaced relation to said rod at one side thereof and parallel thereto, a brushholder pivotally mounted on said rod and torminating in an inclined brush box disposed on the other side of said rod, a brush in said brush box, said brush having an inclined upper surface whereby said brush may be held against the back surface of said brush box, a pressure finger carried by said brushholder and. yieldably pressing on the inclined upper surface of said brush, and means for securing said brushholder in pivotally adjustable position with respect to said adjustment-arm.

4. The combination, in an electric machine having a commutator cylinder, of a brushholdcr-siqiporting member carried by said machine in spaced relation to said com1nutator cylinder, a pivot-pin carried by said supporting member, a brushholder pivotally mounted on said pin and terminating in an inclined brush box, a brush in said brush box, said brush having an inclined upper surface whereby said brush may be held against the back surface of said brush box, a pressure finger carried by said brushholder and yieldably pressing on the inclined upper surface of said brush, and means for securing said bru holder in pi'votally adjustable position with respect to said clamp, the position and angle of said pivot-pin being such that the line joining the pivot-pin and the center of the brush contact surface with the commutator cylinder is substantially tangent to the latter when the commutator surface has worn. away approximately one half of its possible amount, the pivot-pin being at right angles to said line and parallel to the axis of the machine.

5. A brushholder aggregate of the type adapted to be mounted on a single brush rod comprising a clamp for engaging said rod, said clamp carrying a pivot-pin spaced from the rod at one side thereof and parallel thereto, a brushholder pivotally mounted on said pin and terminating in an inclined brush box disposed on the other side of said rod, a brush in said brushbox, a pressure finger carried by said brushholder and yieldably pressing on the upper surface of said brush, and means for securing said brushholder in pivotally adjustable position with respect to said clamp.

6. A brushholder aggregate of the type adapted to be mounted on a single brush rod comprising a clamp for engaging said rod, an adj ustmentarm detachably secured to said clamp, a pivot-pin mounted between said adjustment-arm and said clamp and disposed in spaced relation to said rod at one side thereof and parallel thereto, a brushholder pivotally mounted on said rod and terminating in a brush box disposed on the other side of said rod, a brush in said brush box, a pressure finger carried by said brushholder and yieldably pressing on the upper surface of said brush, and means for securing said brushholder in pivotally adjustable position with respect to said adj ustment-arm.

7 The combination, in an electric machine having a commutator cylinder, of a brushholder-supporting member carried by said machine in spaced relation to said commutator cylinder, a pivot-pin carried by said supporting member, a brushholder pivotally mounted on said pin and terminating in a brush box, a brush in said brush box, a pressure linger carried by said brushholder and yieldably pressing on the upper surface of said brush, and means for securing said brushholder in pivotally adjustable position with respect to said clamp, the position and angle of said pivot-pin being such that the line joining the pivot-pin and the center of the brush contact surface with the commutator cylinder is substantially tangent to the latter when the commutator surface has worn away approximately one-half of its possible amount, the pivotspin being at right angles to said line and parallel to the axis of the machine.

8. The combination, in an electric machine having a commutator cylinder, of a brushholder-supporting member carried by said machine in spaced relation to said commutator cylinder, a pivot-pin carried by said supporting member, a brushholder pivotally mounted on said pin and terminating in an inclined brush box, a brush in said brush box, means for yieldably pressing said brush against the back surface of said brush box and for yieldably pressing said brush toward said commutator cylinder, and means for securing said brushholder in pivotally adjustable position with respect to said clamp, the position and angle of said pivot-pin being such that the line joining the pivot-pin and the center of the brush contact surface with the commutator cylinder is substantially tangent to the latter when the commutator surface has worn away approximately one-half of its possible amount, the pivot-pin being at right angles to said line and parallel to the axis of the machine.

In testimony whereof, I have hereunto subscribed my name this 22nd day of March,

JOHN 'L. BROWVN. 

